Surgical stapling device

ABSTRACT

A surgical stapling device ( 10 ) includes a drive assembly ( 70 ) and a tool assembly ( 16 ). The tool assembly ( 16 ) has a pair of jaws ( 29,31 ) supporting a cartridge assembly ( 32 ) and an anvil ( 30 ). The drive assembly ( 70 ) has a clamping member ( 74 ) that is movable through the tool assembly ( 16 ) to eject staples from the cartridge assembly ( 32 ) into the anvil ( 30 ) and to dissect tissue. The clamp member ( 74 ) includes an extension ( 84 ) that engages one of the jaws ( 29,31 ) to urge the distal end of the engaged jaw ( 29 ) in relation to the other jaw ( 31 ) to urge the tool assembly ( 16 ) towards an insertion position to minimize the diameter of the tool assembly ( 16 ) at a distal end of the tool assembly ( 16 ).

FIELD

This technology is generally related to surgical stapling devices and,more particularly, to surgical stapling devices for endoscopic use.

BACKGROUND

Surgical stapling devices for endoscopic use are well known and commonlyused to minimize patient trauma and reduce patient recovery times.Typically, endoscopic stapling devices include a linear tool assemblythat has an anvil assembly and a cartridge assembly that are coupled toeach other by a pivot member and movable in relation to each otherbetween open and clamped positions. In the clamped position, thestapling device defines a tissue gap between the anvil assembly and thecartridge assembly to receive tissue to be treated.

In use, the tool assembly of an endoscopic stapling device is insertedthrough a small incision in the skin or through a small diametercannula. In order to introduce the tool assembly through a cannulahaving the smallest diameter, the tool assembly is inserted through thecannula in its clamped position. If the tool assembly does not move to afully clamped position, the tool assembly will not be able to enter thecannula.

A continuing need exists in the art for an endoscopic surgical staplingdevice including a tool assembly that moves to its fully clampedposition when the tool assembly is clamped to facilitate insertion ofthe tool assembly through a cannula.

SUMMARY

In aspects, this disclosure generally relates to a stapling device thatincludes a tool assembly and a drive assembly having a clamp member thatsupports a distal extension. The clamp member is movable from aretracted position to a partially advanced position to move the toolassembly from an open position to a clamped position to define a tissuegap within the tool assembly. The distal extension is positioneddistally of the clamp member and engages the tool assembly to urge thetool assembly to an insertion position in which the tool assembly nolonger defines a tissue gap.

One aspect of the disclosure is directed to a stapling device includingan elongate body, a tool assembly, and a drive assembly. The elongatebody has a proximal end portion secured to the handle assembly and adistal end portion. The tool assembly is supported on the distal endportion of the elongate body and includes an anvil and a cartridgeassembly. The cartridge assembly is movable in relation to the anvilfrom between an open position to a clamped position in which thecartridge assembly and the anvil define a predetermined tissue gap. Thecartridge assembly includes a cartridge channel and a staple cartridge.The cartridge channel includes an outer surface defining a ramp. Thedrive assembly includes a drive beam a distal end portion and a dampmember. The clamp member is supported on the distal end portion of thedrive beam and includes a first beam, a second beam, and a verticalstrut interconnecting the first beam and the second beam. The driveassembly is movable between a retracted position and a partiallyadvanced position to move the first and second beams into the ramp tomove the tool assembly from the open position to the clamped position.The drive assembly is movable from the partially advanced position to afully advanced position to actuate the tool assembly. The first beam ofthe clamp member engages the anvil and the second beam of the clampmember engages the cartridge channel of the cartridge assembly. Thesecond beam supports a distal extension that extends distally of thefirst beam and the second beam. The distal extension engages the outersurface of the cartridge channel distally of the ramp when the driveassembly is in the partially advanced position to move the tool assemblyto an insertion position in which a distal end portion of the staplecartridge is engaged with the anvil.

In aspects of the disclosure, the outer surface of the cartridge channelincludes dimples positioned distally of the ramp, and the distalextension of the second beam engages the dimples when the drive assemblyis in the partially advanced position.

In some aspects of the disclosure, the dimples are supported oncantilevered portions of the cartridge channel, wherein the cantileveredportions allow the flexible dimples to flex out of the path of thesecond beam when the drive assembly is moved to the advanced position.

In certain aspects of the disclosure, the distal extension extendsdistally of the first and second beams a distance “X”, wherein “X” isfrom about 0.1 inches and to about 0.25 inches.

In aspects of the disclosure, the distal extension has a width and thesecond beam has a width, and the width of the distal extension issmaller than the width of the second beam.

In some aspects of the disclosure, the stapling device includes arotation knob that is rotatably coupled to the handle assembly andsupports the elongate body such that rotation of the rotation knob inrelation to the handle assembly effects rotation of the elongate bodyand the tool assembly in relation to the handle assembly.

In certain aspects of the disclosure, the stapling device includes ahandle assembly having a stationary handle and a trigger.

Other aspects of this disclosure are directed to a tool assemblyincluding an anvil, a cartridge assembly, and a drive assembly. Thecartridge assembly is movable in relation to the anvil from an openposition to a clamped position in which the cartridge assembly and theanvil define a predetermined maximum tissue gap. The cartridge assemblyincludes a cartridge channel and a staple cartridge. The cartridgechannel includes an outer surface defining a ramp. The drive assemblyincludes a drive beam having a distal end portion and a clamp member.The clamp member is supported on the distal end portion of the drivebeam and includes a first beam, a second beam, and a vertical strutinterconnecting the first beam and the second beam. The drive assemblyis movable between a retracted position and a partially advancedposition to move the tool assembly from the open position to the clampedposition, and movable from the partially advanced position to a fullyadvanced position to actuate the tool assembly. The first beam engagesthe anvil and the second beam engages the cartridge channel of thecartridge assembly. The second beam includes a distal extension thatextends distally of the first beam. The distal extension engages theouter surface of the cartridge channel distally of the ramp when thedrive assembly is in the partially advanced position to move the toolassembly to an insertion position in which the staple cartridge isengaged with the anvil.

Other aspects of this disclosure are directed to a tool assemblyincluding an anvil, a cartridge assembly, and a drive assembly. Thecartridge assembly is movable in relation to the anvil from an openposition to a clamped position in which the cartridge assembly and theanvil define a predetermined maximum tissue gap. The cartridge assemblyincludes a cartridge channel and a staple cartridge. The cartridgechannel has an outer surface defining a ramp. The drive assemblyincludes a drive beam having a distal end portion and a clamp member.The clamp member is supported on the distal end portion of the drivebeam and includes a first beam, a second beam having a first width, anda vertical strut interconnecting the first beam and the second beam. Thedrive assembly is movable between a retracted position and a partiallyadvanced position to move the tool assembly from the open position tothe clamped position, and movable from the partially advanced positionto a fully advanced position to actuate the tool assembly. The firstbeam engages the anvil and the second beam engages the cartridge channelof the cartridge assembly. The second beam includes a distal extensionthat extends distally of the first beam. The distal extension has asecond width smaller than the first width of the second beam. The distalextension engages the outer surface of the cartridge channel distally ofthe ramp when the drive assembly is in the partially advanced positionto move the tool assembly to an insertion position in which the staplecartridge is engaged with the anvil. The outer surface of the cartridgechannel includes dimples positioned distally of the ramp. The distalextension of the second beam engages the dimples when the drive assemblyis in the partially advanced position.

Other features of the disclosure will be appreciated from the followingdescription.

BRIEF DESCRIPTION OF DRAWINGS

Various aspects of the disclosure are described herein below withreference to the drawings, wherein:

FIG. 1 is a perspective view of exemplary aspects of the disclosedsurgical stapling device including a tool assembly in an open position;

FIG. 2 is an exploded, side perspective view of the tool assembly of thestapling device shown in FIG. 1 ;

FIG. 2A is a side perspective view of the cartridge channel of thesurgical stapling device shown in FIG. 1 ;

FIG. 3 is an enlarged view of the indicated area of detail shown in FIG.2 ;

FIG. 4 is an enlarged perspective view of the tool assembly of thesurgical stapling device shown in FIG. 1 in the open position;

FIG. 5 is an enlarged view of the indicated area of detail shown in FIG.4 ;

FIG. 6 is an enlarged perspective view of the tool assembly of thesurgical stapling device shown in FIG. 1 in the clamped position;

FIG. 7 is an enlarged view of the indicated area of detail shown in FIG.6 ;

FIG. 8 is a cross-sectional view taken along section line 8-8 of FIG. 6;

FIG. 9 an enlarged view of the indicated area of detail shown in FIG. 8;

FIG. 10 is a side perspective view of an alternative cartridge channelof disclosed surgical stapling device illustrating other aspects of thedisclosure;

FIG. 11 is an enlarged view of the indicated area of detail shown inFIG. 10 ;

FIG. 12 is a side cross-sectional view of the tool assembly of thesurgical stapling device shown in FIG. 1 with the cartridge channelshown in FIG. 11 with the tool assembly in the clamped position; and

FIG. 13 is an enlarged view of the indicated area of detail shown inFIG. 12 .

DETAILED DESCRIPTION

The disclosed surgical stapling device will now be described in detailwith reference to the drawings in which like reference numeralsdesignate identical or corresponding elements in each of the severalviews. However, it is to be understood that the aspects of thedisclosure are merely exemplary of the disclosure and may be embodied invarious forms. Well-known functions or constructions are not describedin detail to avoid obscuring the disclosure in unnecessary detail.Therefore, specific structural and functional details disclosed hereinare not to be interpreted as limiting, but merely as a basis for theclaims and as a representative basis for teaching one skilled in the artto variously employ the disclosure in virtually any appropriatelydetailed structure. In addition, directional terms such as front, rear,upper, lower, top, bottom, distal, proximal, and similar terms are usedto assist in understanding the description and are not intended to limitthe disclosure.

In this description, the term “proximal” is used generally to refer tothat portion of the device that is closer to a clinician, while the term“distal” is used generally to refer to that portion of the device thatis farther from the clinician. In addition, the term “endoscopic” isused generally used to refer to endoscopic, laparoscopic, arthroscopic,and/or any other procedure conducted through a small diameter incisionor cannula. Further, the term “clinician” is used generally to refer tomedical personnel including doctors, nurses, and support personnel.

The disclosed surgical stapling device includes a tool assembly having apair of jaws supporting a cartridge assembly and an anvil assembly. Thejaws are pivotably coupled to each other and are movable in relation toeach other between open and clamped positions. The stapling deviceincludes a drive assembly having a clamping member that is movablethrough the tool assembly to eject staples from the cartridge assemblyinto the anvil assembly and to dissect tissue. The clamp member includesfirst and second beams that are vertically aligned and engage the anviland cartridge assemblies to move the anvil and cartridge assembliesbetween the open and clamped positions. In the clamped position, theanvil and cartridge assemblies define a maximum tissue gap. The clampmember includes an extension that extends distally of the first andsecond beams and engages one of the jaws to urge the distal end of thecartridge assembly or anvil assembly supported on the engaged jaw to aninsertion position engaged with the other of the cartridge assembly oranvil assembly supported on the other jaw to minimize the diameter ofthe tool assembly at a distal end of the tool assembly.

FIG. 1 illustrates exemplary aspects of the disclosed surgical staplingdevice shown generally as stapling device 10. The stapling device 10includes a handle assembly 12, an elongate body 14 defining alongitudinal axis “X”, and a tool assembly 16. The handle assembly 12includes a stationary handle 18 and a trigger 20 that is movable inrelation to the stationary handle 18 to actuate the tool assembly 16. Inaspects of the disclosure, the stapling device 10 includes a rotationknob 22 and an articulation lever 24. The rotation knob 22 is coupled tothe handle assembly 12 and to the elongate body 14 to facilitaterotation of the elongate body 14 and tool assembly 16 in relation to thehandle assembly 12 about the longitudinal axis “X”. The articulationlever 24 is coupled to the tool assembly 16 to articulate the toolassembly 16 from a position aligned with the longitudinal axis “X” topositions defining acute angles with the longitudinal axis “X”. In someaspects of the stapling device 10, the handle assembly 12 includesretraction knobs 26 for retracting a drive assembly of the staplingdevice 10. For a more detailed description of exemplary aspects of thehandle assembly 12 of the stapling device 10, see, e.g., U.S. Pat. No.6,241,139 (“the '139 patent”). Although the handle assembly 12 isillustrated as a manually operated handle assembly, it is envisionedthat the handle assembly 12 could be a powered handle assembly such asdescribed in U.S. Pat. No. 9,055,943.

FIG. 2 illustrates the tool assembly 16 of the stapling device 10 (FIG.1 ) which includes a first jaw 29 supporting an anvil 30 and a secondjaw 31 supporting a cartridge assembly 32. The first and second jaws 29,31 are coupled together with pivot members 36 such that the cartridgeassembly 32 can pivot in relation to the anvil 30 between an openposition (FIG. 1 ) and a clamped position (FIG. 8 ). Although thecartridge assembly 32 is illustrated as pivoting towards a stationaryanvil 30, it is envisioned that the anvil 30 could pivot towards astationary cartridge assembly 32.

The cartridge assembly 32 includes a cartridge channel 38 and a staplecartridge 40. The staple cartridge 40 includes a cartridge body 42 thatdefines a knife slot 40 a and supports an actuation sled 43 (FIG. 9 ), aplurality of staples (not shown), and pushers (not shown). For adetailed description of an exemplary staple cartridge, see, e.g., the'139 patent.

FIG. 2A illustrates the cartridge channel 38 which includes a body 50having an outer wall 52 and spaced side walls 54. The outer wall 52defines an elongate recess 56 and an elongate slot 56 a that extendswithin the recess 56 from a position adjacent a distal end of thecartridge channel 38 to a position adjacent the proximal end of thecartridge channel 38. The recess 56 includes a ramp 60 that ispositioned on opposite sides of the elongate slot 56 adjacent theproximal end of the cartridge channel 38. The body 50 of the cartridgechannel 38 is configured to releasably receive the staple cartridge 40.Upon firing of the stapling device 10, a spent or used staple cartridge40 can be removed from the cartridge channel 38 and replaced with afresh or new staple cartridge 40 to facilitate reuse of the staplingdevice 10.

FIGS. 2 and 3 illustrate a drive assembly 70 of the stapling device 10.The drive assembly 70 includes a drive beam 72 and a clamp member 74that is secured to a distal end portion 72 a of the drive beam 72. Incertain aspects of the disclosure, the drive beam 72 is formed fromstacked sheets of a flexible material, e.g., stainless steel, and theclamp member 74 is coupled to the drive beam 72 using a dove-tail typeconnection 78 (FIG. 3 ). The clamp member 74 includes a first beam 76, asecond beam 78 and a vertical strut 80 that interconnects the first beam76 and the second beam 78. The first beam 76 is vertically aligned withsecond beam 78 and is engaged with the anvil 30. The second beam 78 isreceived within the elongate recess 56 of the cartridge channel 38. Thevertical strut 80 extends through the knife slot 40 a in the staplecartridge 40 and through the slot 56 a in the cartridge channel 38. Thedrive assembly 70 is movable along the tool assembly 16 from a retractedposition to an advanced position to move the tool assembly from its openposition to its clamped position and to subsequently eject staples (notshown) from the staple cartridge 40. In the clamped position, the clampmember 74 is configured to define a predetermined tissue gap “G” betweenthe anvil 30 and the staple cartridge 40. In some aspects of thedisclosure, the vertical strut 80 supports a knife blade 82 that isaligned with the tissue gap defined between the anvil 30 and the staplecartridge 40 to cut tissue clamped between the anvil 30 and the staplecartridge 40.

As described above, the first beam 76 and the second beam 78 of theclamp member are in substantial vertical alignment. More specifically,the first beam 76 is positioned above the second beam 78 and is spacedfrom the second beam 78 by the vertical strut 80 such that a distal endof the first 76 is in substantial vertical alignment with the distal endof the second beam 78.

In aspects of the disclosure, the second beam 78 supports an extension84 that is secured to the distal end of the second beam 78 and extendsdistally from the distal end of the second beam 78 a distance “X”,wherein “X” is from about 0.1 inches to about 0.25 inches. (FIG. 3 ). Insome aspects of the disclosure, the extension 84 is integrally ormonolithically formed with the second beam 78.

FIGS. 4 and 5 illustrate the tool assembly 16 in the open position withthe drive assembly 70 (FIG. 2 ) in the retracted position. In theretracted position, the first and second beams 76, 78 and the distalextension 84 of the clamp member 74 of the drive assembly 70 arepositioned proximally of the ramp 60 of the cartridge channel 38. Inthis position, the cartridge assembly 32 is pivoted outwardly of theanvil 30.

FIGS. 6-9 illustrate the tool assembly 16 in the clamped position withthe drive assembly 70 (FIG. 2 ) advanced in the direction of arrow “A”to a partially advanced position. In the clamped position, the secondbeam 78 of the clamp member 74 is engaged with the ramp 60 on thecartridge channel 38 and the first beam 76 is engaged with the anvilfirst jaw 29 supporting the anvil 30. In addition, the extension 84 onthe second beam 78 extends distally of the ramp 60 and is engaged withan outer surface of the cartridge channel 38 within the recess 56. Whenthe second beam 78 of the clamp member 74 engages and moves along theramp 60, the cartridge channel 38 and the staple cartridge 40 supportedwithin the cartridge channel 38 are pivoted in the direction of arrow“B” in FIG. 6 to move the tool assembly 16 from the open position (FIG.4 ) to the clamped position. The extension 84 on the second beam 78extends forward of the ramp 60 and engages the cartridge channel 38 tourge the cartridge channel 38 towards the anvil 30 to an insertionposition (FIG. 8 ) in which the staple cartridge 40 engages the anvil 30to close the tissue gap “G” defined between the staple cartridge 40 andthe anvil 30 and/or, to at least maintain the cartridge channel 38 in aposition spaced from the anvil 30 a distance no greater than thepredetermined tissue gap “G”, i.e, the extension 84 prevents outwarddeflection of the cartridge channel 38 that would allow the tissue gap“G’ to exceed the predetermined tissue gap “G”. I This is especiallyimportant in stapling devices used for multiple firings wherein outwarddeflection of the cartridge channel 38 may occur due to the prior use onthick tissue. In aspects of the disclosure, the distal extension 84 hasa width that is less than the width of the second beam 78.

FIGS. 10-13 illustrate a tool assembly 116 including an alternativecartridge channel shown generally as cartridge channel 138 includingother aspects of the disclosure. The cartridge channel 138 issubstantially similar to cartridge channel 38 (FIG. 3 ) but includesflexible dimples 140 on an outer surface of the cartridge channel 138.The dimples 140 are supported on cantilevered portions 142 of thecartridge channel 138. The dimples 140 define raised surfaces thatengage the extension 84 (FIG. 13 ) supported on the second beam 78 ofthe clamp member 74 when the drive assembly 70 (FIG. 3 ) is advanced inthe direction of arrow “C” in FIG. 13 to move the tool assembly 16 (FIG.8 ) to the clamped position. Engagement between the dimples 140 and theextension 84 increases the force on the cartridge assembly 32 applied bythe extension 84 to urge the cartridge assembly 132 (FIG. 12 ) towardsthe anvil 30 to the insertion position in which the distal end portionof the staple cartridge 40 engages the distal end portion of the anvil30 and/or the tool assembly is maintained in the clamped position inwhich the tissue gap between the cartridge assembly 32 and the anvil 30at a distal end of the tool assembly 16 does not exceed a predeterminedtissue gap “G”. The cantilevered portions 142 allow the dimples 140 toflex inwardly in the direction of arrow “D” out of the path of thesecond beam 78 (FIG. 13 ) of the clamp member 74. This allows the clampmember 74 to pass over the dimples 140 when the clamp member 74 isadvanced to fire staples from the stapling device 10.

Persons skilled in the art will understand that the devices and methodsspecifically described herein and illustrated in the accompanyingdrawings are non-limiting exemplary aspects of the disclosure. It isenvisioned that the elements and features illustrated or described inconnection with one exemplary embodiment may be combined with theelements and features of another without departing from the scope of thepresent disclosure. As well, one skilled in the art will appreciatefurther features and advantages of the disclosure based on theabove-described aspects of the disclosure. Accordingly, the disclosureis not to be limited by what has been particularly shown and described,except as indicated by the appended claims.

What is claimed is:
 1. A stapling device comprising: an elongate bodyhaving a proximal end portion and a distal end portion, the proximal endportion secured to the handle assembly; a tool assembly supported on thedistal end portion of the elongate body, the tool assembly including ananvil and a cartridge assembly, the cartridge assembly being movable inrelation to the anvil from between an open position to a clampedposition in which the cartridge assembly and the anvil define apredetermined tissue gap, the cartridge assembly including a cartridgechannel and a staple cartridge having a distal end portion, thecartridge channel including an outer surface defining a ramp; and adrive assembly including a drive beam and a clamp member, the drive beamhaving a distal end portion, the clamp member supported on the distalend portion of the drive beam and including a first beam, a second beam,and a vertical strut interconnecting the first beam and the second beam,the drive assembly movable between a retracted position and a partiallyadvanced position to move the first and second beams into the ramp tomove the tool assembly from the open position to the clamped position,and movable from the partially advanced position to a fully advancedposition to actuate the tool assembly, the first beam engaging the anviland the second beam engaging the cartridge channel of the cartridgeassembly; wherein the second beam supports a distal extension thatextends distally of the first beam and the second beam, the distalextension engaging the outer surface of the cartridge channel distallyof the ramp when the drive assembly is in the partially advancedposition to maintain the tool assembly in the clamped position.
 2. Thestapling device of claim 1, wherein the outer surface of the cartridgechannel includes dimples positioned distally of the ramp, the distalextension of the second beam engaging the dimples when the driveassembly is in the partially advanced position.
 3. The stapling deviceof claim 2, wherein the dimples are supported on cantilevered portionsof the cartridge channel, the cantilevered portions allowing theflexible dimples to flex out of the path of the second beam when thedrive assembly is moved to the advanced position.
 4. The stapling deviceof claim 1, wherein the distal extension extends distally of the firstand second beams a distance “X”, wherein “X” is from about 0.1 inchesand to about 0.25 inches.
 5. The stapling device of claim 1, wherein thedistal extension has a width and the second beam has a width, the widthof the distal extension being smaller than the width of the second beam.6. The stapling device of claim 1, further including a rotation knob,the rotation knob being rotatably coupled to the handle assembly andsupporting the elongate body, wherein rotation of the rotation knob inrelation to the handle assembly effects rotation of the elongate bodyand the tool assembly in relation to the handle assembly.
 7. Thestapling device of claim 1, further including a handle assembly having astationary handle and a trigger.
 8. A tool assembly comprising: ananvil; a cartridge assembly movable in relation to the anvil from anopen position to a clamped position in which the cartridge assembly andthe anvil define a predetermined maximum tissue gap, the cartridgeassembly including a cartridge channel and a staple cartridge having adistal end portion, the cartridge channel including an outer surfacedefining a ramp; and a drive assembly including a drive beam and a clampmember, the drive beam having a distal end portion, the clamp membersupported on the distal end portion of the drive beam and including afirst beam, a second beam, and a vertical strut interconnecting thefirst beam and the second beam, the drive assembly movable between aretracted position and a partially advanced position to move the toolassembly from the open position to the clamped position, and movablefrom the partially advanced position to a fully advanced position toactuate the tool assembly, the first beam engaging the anvil and thesecond beam engaging the cartridge channel of the cartridge assembly;wherein the second beam includes a distal extension that extendsdistally of the first beam, the distal extension engaging the outersurface of the cartridge channel distally of the ramp when the driveassembly is in the partially advanced position to maintain the toolassembly in the clamped position.
 9. The stapling device of claim 8,wherein the outer surface of the cartridge channel includes dimplespositioned distally of the ramp, the distal extension of the second beamengaging the dimples when the drive assembly is in the partiallyadvanced position.
 10. The stapling device of claim 9, wherein thedimples are supported on cantilevered portions of the cartridge channel,the cantilevered portions allowing the flexible dimples to flex out ofthe path of the second beam when the drive assembly is moved to theadvanced position.
 11. The stapling device of claim 8, wherein thedistal extension extends distally of the first and second beams adistance “X”, wherein “X” is from about 0.1 inches and to about 0.25inches.
 12. A tool assembly comprising: an anvil; a cartridge assemblymovable in relation to the anvil from between an open position and aclamped position in which the cartridge assembly and the anvil define apredetermined maximum tissue gap, the cartridge assembly including acartridge channel and a staple cartridge having a distal end portion,the cartridge channel including an outer surface defining a ramp; and adrive assembly including a drive beam and a clamp member, the drive beamhaving a distal end portion, the clamp member supported on the distalend portion of the drive beam and including a first beam, a second beam,and a vertical strut interconnecting the first beam and the second beam,the second beam having a first width, the drive assembly movable betweena retracted position and a partially advanced position to move the toolassembly from the open position to the clamped position, and movablefrom the partially advanced position to a fully advanced position toactuate the tool assembly, the first beam engaging the anvil and thesecond beam engaging the cartridge channel of the cartridge assembly;the second beam including a distal extension that extends distally ofthe first beam, the distal extension having a second width smaller thanthe first width of the second beam, the distal extension engaging theouter surface of the cartridge channel distally of the ramp when thedrive assembly is in the partially advanced position to maintain thetool assembly in the clamped position, wherein the outer surface of thecartridge channel includes dimples positioned distally of the ramp, thedistal extension of the second beam engaging the dimples when the driveassembly is in the partially advanced position.
 13. The stapling deviceof claim 12, wherein the dimples are supported on cantilevered portionsof the cartridge channel, the cantilevered portions allowing theflexible dimples to flex out of the path of the second beam when thedrive assembly is moved to the advanced position.
 14. The staplingdevice of claim 12, wherein the distal extension extends distally of thefirst and second beams a distance “X”, wherein “X” is from about 0.1inches and to about 0.25 inches.